This invention relates to chemical compounds which are useful in converting liquids to a non-pourable state, for example. The invention is particularly useful in medical applications for converting waste (infectious) medical liquids or semi-liquids to a substantially non-pourable state for ready handling and disposal.
In the field of liquid waste handling, there are known several powdered super-absorbent compounds (at times referred to herein as xe2x80x9cabsorbentsxe2x80x9d) which can solidify, or convert to a gel, a large volume of liquid relative to the volume or weight of the absorbent introduced into the liquid. One major use of such absorbents is to convert a volume of liquid to a solid, semi-solid (e.g., a gel) form to make the liquid sufficiently stable for recovery of spilled liquid or to convert the liquid into a form which is reasonably stable for clean-up (spills), handling (shipping/transfer), storage and/or disposal. With many liquid wastes, employee safety and/or environmental concerns dictate quick action to minimize the distribution of a spilled flowable waste, hence the need for rapid solidification of the liquid. In certain medical situations, time is of the essence and avoidance of inadvertent spillage of liquid waste is most important, hence another example where rapid solidification of such liquid waste is important, or even critical.
xe2x80x9cSolidificationxe2x80x9d or xe2x80x9cstabilizationxe2x80x9d, as these terms are used herein is intended to refer to the alteration of the state of a flowable material (usually a liquid) to a substantially non-flowable material. The xe2x80x9cflowablexe2x80x9d material may be a liquid or in a gel or semi-solid state, so that if the material were contained within an open-top vessel, the material would readily xe2x80x9cflowxe2x80x9d from the vessel when the vessel was tilted, for example. A xe2x80x9cnon-flowablexe2x80x9d material may be a solid or substantially a solid (as in a gel) such that the material would not readily flow from a tilted vessel containing the material. xe2x80x9cSolidifierxe2x80x9d, as used herein, is intended to include two or more absorbents. The solidifier may comprise a single mixture of the absorbents, or in other instances, may comprise two or more absorbents (or mixtures of absorbents).
In the prior art super-absorbents have been employed in many applications, such as in oil spills where the super-absorbent, applied in liquid or powder form stems the distribution of the spill and renders the oil more readily retrieved or collected. In medial applications, super-absorbents have been used heretofore for stabilizing liquid infectious waste within a container against spillage through inadvertent tipping of the container in the course of a medical procedure, or during transfer, storage and/or disposal of the waste.
Super absorbents may be characterized by a variety of properties. In the present invention, one such property is the apparent density (also termed xe2x80x9cbulk densityxe2x80x9d) of the super absorbent relative to other super absorbents and/or relative to the density of the liquid sought to be stabilized. For example, the super absorbent may either sink or float with respect to the liquid sought to be stabilized. For example, in the instance of an oil spill, the immediate concern commonly is to deter seepage of the oil into the ground. In this situation, an absorbent having a density greater than the oil would be desired so that the absorbent would xe2x80x9csinkxe2x80x9d relative to the oil and solidification of the oil would commence at the bottom of the layer of spilled oil. On the other hand, it might be desirable when dealing with a container of liquid waste, that the solidification commence adjacent the surface of the liquid to quickly form a xe2x80x9csolid capxe2x80x9d on the surface of the liquid whereby spillage or splashing of the liquid from the container is minimized while the remainder of the liquid in the container is being stabilized.
It has been found by the present inventor that in certain instances, the apparent density of the absorbent, relative to the density of the liquid sought to be stabilized, can present problems, in that a relatively lower density absorbent may quickly form a cap on the surface of a liquid and preclude the migration of absorbent to other portions of the liquid. Vice versa, if the absorbent is more dense than the liquid, the absorbent quickly sinks to the bottom of a container of liquid and commences solidification of that liquid adjacent the bottom of the container and traps absorbent within the solidified liquid so that there is little, slow or no solidification of the remaining liquid within the container. The mixture(s) may be packaged for controlled release into a liquid sought to stabilized.
It is an object of the present invention to provide a novel solidifier for flowable materials, such as liquids.
It is another object of the present invention to provide a method for the controlled stabilization of a flowable material throughout the overall volume of the flowable material.